AAP: One of the world’s foremost climate change experts believes not enough is being done to tackle the problem. But Professor David Griggs, the former director of the Hadley Centre for Climate Prediction and Research in the United Kingdom, said he was encouraged by the progress made in the past 20 years. Prof Griggs, now the director of the Monash Sustainability Institute in Melbourne, said there was unequivocal evidence that the earth had warmed dramatically in the past half a …